The overall objective of this proposed research is to elucidate the unique relationship of the central nervous system (CNS) and the immune system as a "network" in humans with primary malignant brain tumors. Further definition of the cellular mechanisms associated with impaired host immunocompetence of brain tumor patients will be determined by characterizing lymphocyte subsets via number and affinity of lectin surface receptors and assessing alterations in translocation receptor movement and in stability of sheep erythrocyte receptors. The relationship of cyclic nucleotides and hormones with lymphocyte activation also will be studied in these patients. These quantitative and qualitative cellular changes will be correlated with alterations in host immunocompetence. Furthermore, the ability of various bran extracts, sera (fraction), and hormones to induce similar quantitative and qualitative changes in normal lymphocytes will be assessed. Classical immunochemical and biochemical techniques will be utilized to isolated and characterize immune-inhibitory fractions from tumor extracts and sera of tumor patients and correlated with changes in lymphocyte number and function as well as general and tumor associated immunity. Finally, these immunological probes will be sequentially correlated with the clinical course of each patient.